JPH01107528A - Forming method for pattern - Google Patents

Abstract

PURPOSE:To form a pattern having a good shape and to improve the yield of an element by forming a film of a negative type resist on a substrate, then selectively exposing it with a far ultraviolet ray, thereafter exposing the whole surface with an ultraviolet ray, and developing it. CONSTITUTION:A substrate 1 of semiconductor or the like is coated, for example, with 0.1mum of a negative type resist, and a resist layer 2 is obtained by oven prebaking at 80 deg.C for 20min. Then, it is selectively exposed through a mask 4 by an excimer laser light 3 of an energy of 50mJ/cm<2>. The whole surface is exposed with an ultraviolet light 6 from an Hg lamp with the energy of 50mJ/cm<2>, and developed with a developer for 1min to form a pattern 2a, thereby obtaining a line and space pattern having 0.5mum of thickness (87 deg. of inclination) and improved for its contrast. Thus, a fine pattern having a high contrast with the far ultraviolet pay and the excimer laser can be obtained by the negative type resist, thereby improving the yield of a semiconductor element.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a pattern forming method in a semiconductor manufacturing process.

BACKGROUND OF THE INVENTION In recent years, pattern formation using short wavelength excimer laser light has attracted attention in order to improve the resolution of resist patterns [for example, V, Po71θta7! ,
7” Rising of SPI (Pro
c of' 8p[), 633, Pa (19
ae)'l.

However, when trying to form a pattern with an excimer laser using a negative resist, the resist absorbs too much short wavelength light on its surface, making it difficult for the light to reach the bottom of the resist, resulting in a poor inverted trapezoidal profile. It turns out that all you get is a pattern.

A conventional pattern forming method using a negative resist will be described with reference to FIG.

A negative resist RD200ON (Hitachi Chemical) was applied to a thickness of 1.017 zm on the substrate 1, and a resist layer 2 was formed by pre-baking in an oven at 80° C. for 20 minutes (FIG. 2(a)). After this, the KrF excimer laser beam 3 was heated at 12011 J/c.
! The pattern 2b was selectively exposed to light through a mask 4 using an energy of 2 (FIG. 2(b)), and development was performed for 1 minute using an HD developer to form a pattern 2b (FIG. 2(C)).

However, pattern 2b was a 0.5 μm line-and-space pattern with an inverted trapezoid shape and a poor profile.

Problems to be Solved by the Invention As described above, the poorly shaped inverted trapezoidal pattern caused by surface light absorption of the resist leads to deterioration of dimensional accuracy in the subsequent etching process and ion implantation process, and as a result, the yield rate of the device decreases. leading to a decline.

An object of the present invention is to form a well-shaped pattern using a negative resist using excimer laser light or deep ultraviolet light.

Means for Solving the Problems The present invention is characterized in that, in order to solve the problems of the conventional example, after selective exposure with deep ultraviolet light, the entire surface is exposed with ultraviolet light.

Operation The method of the present invention combines deep ultraviolet and ultraviolet exposure. The initial deep ultraviolet exposure improves the transmittance of the negative resist in the ultraviolet region. Therefore, only in the selective far-UV exposed areas, the UV light can easily reach the bottom of the resist, and after development.

In the end, the original pattern of the deep ultraviolet exposed area is obtained. This pattern is different from the conventional one because the ultraviolet light completely reaches the bottom, resulting in a good shape.

Note that when the entire surface is irradiated with ultraviolet rays, it is possible that the surface of the unexposed areas of the first deep ultraviolet exposure may also be crosslinked.

It was found that the penetration speed of ultraviolet light into the deep ultraviolet-exposed area increases due to the increase in transmittance, so that it hardly reaches the point where crosslinking of the surface occurs.

It has also been found that even if crosslinking occurs on one surface, it can be sufficiently developed (removed) during development.

Note that it is clear that the exposure time for deep ultraviolet light may be shorter than when it is used for normal resist pattern formation.

Embodiment An embodiment of the pattern forming method of the present invention will be described with reference to FIG. Negative type RD on a substrate 1 such as a semiconductor
Apply 200ON (Hitachi Chemical) at 1.0pH1 and heat to 80°C.
Pre-bake in the oven for 20 minutes.

A resist layer 2 was obtained (FIG. 1(a)). After this.

KrF excimer laser light 3 was selectively exposed through a mask 4 at an energy of so IIJ/- (FIG. 1(b)). As a result, the surface portion of the resist 2 is irradiated with deep ultraviolet light, and the transmittance in the ultraviolet region increases from 30% before exposure to 7.
It rose to 0% (value at 430 nll). Then, 60IIIJ/c of ultraviolet light from an Hg lamp was applied to the entire surface.
! (Fig. 1 (C)).

After that, development was performed for 91 minutes using RD developer, and pattern 2
1L was formed (Fig. 1(d)). Pattern 2& is a 0.6μl line with improved contrast (87° inclination).
It was an and space pattern.

In addition, when using excimer laser light from ArF or
Similar results were obtained when using 1-line (AES nm) light.

Effects of the Invention By using the method of the present invention, it is possible to obtain a fine, high-contrast pattern using deep ultraviolet rays or excimer laser light using a negative-produced resist, leading to improved yields of semiconductor devices and industrial applications. High value.

[Brief explanation of the drawing]

FIGS. 1(a) to 1(1) are process cross-sectional views of a pattern forming method according to an embodiment of the present invention, and FIGS. 2(IL) to (0) are process cross-sectional views of a conventional pattern forming method. 1...Substrate, 2...Negative resist, 3...
... KrF excimer laser light, 4 ... mask, 6 ... ultraviolet light. 2a... pattern. Name of agent: Patent attorney Toshio Nakao and 1 other person/-
-One board

Claims (2)

[Claims] (1) A pattern forming method in which a negative resist film is formed on a substrate, selectively exposed to deep ultraviolet rays, and then the entire surface is exposed to ultraviolet rays and developed. (2) The pattern forming method according to claim 1, wherein the far ultraviolet light is pulsed light of an excimer laser emitted from ArF, KrF, or XeCl.